Recovering oils



Patented Oct. 6, 1925.

UNITED. STATES PA 1,556,396 TENT OFFICE...

VICTOR S. ALLIEN, OF WILMINGTON, DELAWARE, ASSIGNOR T0 DARCO CORIORA- TION, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE.

RECOVERING OILS.

No Drawing. I

To all whom it may concern:

Be it known that I, VIoToR S. ALLIEN, a citizen of the United States, residing at Wilmington, in the county of New Castle and State of Delaware, have invented certain new and useful Improvements in Recovering Oils, of which the following is a specification.

This invention relates to recovering oils; and it comprises a method of utilizing used and dirty lubricating oil, such as -crank case oil, wherein such oil is submitted to a methodical purification, including a treatment with decolorizing carbon to remove colloid matter including colloid carbon; all

as more fully hereinafter set forth and as r I claimed.

While derived from high grade oils and still containing much of the original material in chemically and physically unchanged state,

- it is difiicult to recover good lubricating oil from it, or indeed to do anything with it.

In garages of any size there is frequently a large accumulation of what is known as crank case oil, which may' be taken as typical of these waste oils. vCrank case oil contains, in addition to the original lubricating oil, a greater or less proportion of more volatile oils ofthe nature of gasoline and kerosene; these volatile oils coming partly from cracking of the lubricating oil by heat and partly by absorption'from the explosive charge of the engine. It also contains carbon, finely divided metal and other solid matters. In part this solid material is in coarse form but in part it is so fine as to be really of a colloid nature. This colloid, finely divided matter (carbon, etc.) is particularly hard to remove and is responsible for most of the difliculty in devising methods of utilizing these waste oils.

I have found that a good grade of lubrieating oil can be recovered from these waste materials by certain methodical treatments thereof; these treatments including one with finely divided activated carbon of the nature of that which is now as decolorizing carbon. A particularly good variety of this carbon is described and claimed in the Mumford Patent No. 1,286,187.

I find that on treating the oil at a proper known on the market Applicati'on'filed January 19, 1922. Serial- No. 530,454.

stage in the purification with decolorizing carbon of this nature, the colloid carbon of the oil is taken up and effectually removed by the decolorizing carbon, giving a bright, clear oil. Incidentally, the decolorizing carbon often effects a considerable decolorization by removing dissolved coloring matters; but, for the present purposes, its power of removing colloided carbon and solids is more important.- Where the matter in colloid suspension is substantially only carbon, as it frequently is, and particularly with crank case oil, or with any oil which has been settled or treated to remove coarse stuff, the result of the treatment of the oil with the decolorizing carbon is to form a compound body of carbon of high pigmentary value. It may be used as a substitute for lampblack and the like. The colloid carbon of these used oils is of course in a state of excessively fine division and of good pigmentary value. I regard the Mumford material as particularly advantageous for the present purposes slnce its carbon-gathering power is much higher than that of other de- 1 colorizing carbons, so that not only is less of it required to do the necessary work but the pigmentary value of the compound carbon recovered is much greater owing to the high proportion of colloid carbon therein.

In a specific embodiment of the present invention, treating crank case oil, the oil gathered up from the garages is allowed to settle for a time at the ordinary temperature to free it, as far as possible, of coarser solid impurities. Usually it is allowed to settled about 24 hours. It is then separatedfrom the mud, warmed and again settled. A temperature of about 130 F. and a settling period of about 12 hours are satisfactory. The separated impurities of both these settling. treatments may be filterpressed to regain some of the oil and the solids of the press cake burned or otherwise v in the second settling operation. The oil is next heated in any suitable steam still to remove gasoline and .kerosene. Any still provided with means for introducing low pressure steam may be used for this purpose. Instead of stripping the oil of volatiles by steam it may be filmed out over heating surfaces in appropriate apparatus of well known types, with or without the use of vacuum, but steam distillation is ordinarily simpler and better. After passing in steam for a time, the lubricating oil becomes free of volatile oils and resumes its original high flash and fire tests. The volatile oils (gasoline and kerosene) recovered in steaming may be treated and utilized in any suitable manner, not here important. Finally it is best topass the oil once more through a centrifugal to remove any solid matter separated in the heating operation.

In this procedure if decolorizing carbon is used at one or more points in the succession of steps just described the final product is a good and useful lubricating oil. The decolorizing carbon may, for example,

' be added to the oil after the warm settling and before the first treatment in a centrifugal. In so doing, the centrifugal removes the added decolorizing carbon as well as the colloid matter taken up by it, and the oil ismore easily handled in the steam still. Or the decolorizing carbon may be added to the oil after the first treatment in a centrifugal and prior to distillation. In so doing, it goes into the still with the oil and is removed in the subsequent treatment in a centrifugal. Or it may be added after the distillation with steam and prior to the second treatment in a centrifugal. Added at any point in the succession of steps, it has the result of removing colloided matter as well as dissolved impurities and of facilitating the subsequent treatments.

Ordinarily, after all the treatments described I give the oil a final treatment with fullers earth. By using the decolorizing reeaaee carbon somewhere in the succession of steps prior to the use of fullers earth, the amount of fullers earth required is very little thereby making not only a saving in the amount of fullers earth otherwise necessary to effect any substantial purification of the oil but in the amount of oil which must be lost in discarded earth. The use of fullers earth alone with oils of this class in such a process as that just stated is very unsatisfactory; but where decolorizing carbon has been used in the manner described for removing colloid carbon during the purification operation, the use of fullers earth is here as satisfactory as with other oils in the ordinary methods of treatment.

In the stated method of operating oil of uniform quality and light color is easily obtained.

The use of fullers earth is not necessary in the present method, although it is often convenient. Decolorizing carbon used in the manner stated will give a satisfactory product without the use of fullers earth.

Ordinarily, in the steam still, I raise the temperature of the oil to about 450 to 500 F. and continue the distillation until a residual oil of a flash point of about 420 is obtained.

What I claim is In the treatment of crank case oil and the like to recover lubricating oil therefronn.

the process which comprises settling said oilin a warm condition, removing further impurities by centrifugal action, steaming the oil to free it of volatile oils, removing solids by centrifugal action and VICTOR s; ALLIEN.

finally treating with fullers earth, an addition of decolorizing carbon being made to the. oil prior to 

